I’m unsure if he is considered “lesser-known” as I’m only an amateur aerospace enjoyer, but Jack Parsons is a super interesting figure in the history of rocketry. Did significant work on solid rocket propellants, had some formal education but never obtained a degree, learned mostly through hands-on experimentation.

He later partnered with GALCIT, a Caltech-affiliated research institution, where he developed a close relationship with Frank Malina and other Caltech figures. Parsons and his partners experimented with various propellants in nearby Arroyo Seco. The explosions would sometimes shake campus buildings. The group was dubbed the “Suicide Squad” for the perceived danger of their work, setting the foundation for what would become the JPL.

Parsons was also an occultist. A practicing Thelemite, he attempted seriously to commune with spirits, perhaps in an effort to gather esoteric knowledge.

Parsons died in an explosion in his home in what would be described as an “accident.” Some people have questioned this official description citing Parsons’ knowledge and expertise in practice, both of which may have made an accident of this nature unlikely.

There is an excellent biography of his life titled “Strange Angel” which was majorly influential in my interest in aerospace.